JP2002300578A - Video transmission equipment - Google Patents

Abstract

(57) [Problem] To provide a video transmission system capable of displaying and storing a moving image of an imaging target using compressed data while displaying and storing non-compressed data of a quasi-moving image. SOLUTION: In addition to a system for outputting uncompressed data, the system has a system for performing data compression and outputting the data, and it is possible to transmit compressed data and uncompressed data on two channels while appropriately switching these two outputs. A video transmission device with a simple control circuit that receives compressed data while receiving uncompressed data, and performs display and image processing using a quasi-moving image based on uncompressed data, Display and accumulation of moving images can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a video transmission system using a high-speed digital transmission bus standard that has a guaranteed bandwidth transmission mode, such as USB or USB (Universal Serial Bus), and that can construct a network.

[0002]

2. Description of the Related Art A conventional non-compressed data video transmission apparatus having a high-speed digital transmission interface having a guaranteed bandwidth transmission mode can transmit only one channel of uncompressed data. This is because the transmission LSI supports multi-channel transmission, but the bandwidth is narrow, and furthermore, a PC (personal computer) which is a video receiving device
This is because the processing speed is incapable of receiving data of multiple channels. At present, these problems are being solved, the bandwidth has been widened, and the processing speed of a PC, which is a current video receiving apparatus, has been dramatically improved. Here, a conventional video transmission device that outputs uncompressed data will be described with reference to FIG. When a command to start transmitting video data is received by the transmission / reception LSI 28 connected via the high-speed digital transmission path, the CPU 30 confirms the command and transmits the command to the video control command decoder 29.
Controls the DSP (Digital Signal Processor) unit 25, the data format conversion unit 26, and the CCD timing generation unit 31. The video signal output from the CCD 22 is subjected to noise removal by the process processing unit 23 and amplified. These signals are digitized by the A / D converter 24 and processed by the DSP 25. These signals are converted by the data format converter 26 into preset video data such as an image size, the number of bits per pixel, and a color format. The converted data is stored in the buffer 27 and finally input to the transmission / reception LSI 28 and transmitted to the high-speed digital transmission path. When the video transmission device 32 is set so that an external trigger can be input, the input external trigger pulse is received by the CCD timing generation unit 31, and a clock for one frame of the CCD is generated at this timing. Thus, one frame of data is output from the CCD 22.

[0003]

In a conventional uncompressed data output video transmission device having a high-speed digital interface, display and moving image storage in the video reception device are performed because the output data is uncompressed data. Processing speed and the bandwidth of a high-speed digital transmission line. For this reason, the conventional video transmission device has a wide occupied band because it is uncompressed data even if the processing of the video reception device is high-speed.
In some cases, it was not even possible to display images for channels.
In such a case, the band has been narrowed by reducing the frame rate or the quality of the image. Therefore, high image quality,
When receiving high-resolution uncompressed data, video data is received at a reduced frame rate, so that it is not possible to monitor and store a moving image of an imaging target with a certain degree of real-time property. Here, the moving image refers to video data without missing frames corresponding to 30 frames of the NTSC signal and 25 frames of the PAL signal. An object of the present invention is to eliminate these drawbacks and to realize a video transmission system capable of displaying and storing a moving image of an imaging target using compressed data while displaying and storing uncompressed data of a quasi-moving image. .

[0004]

In order to achieve the above object, the present invention has a system for performing data compression and outputting in addition to a system for outputting non-compressed data.
Compressed data and uncompressed data each 2 while switching
This is a video transmission device having a control circuit capable of transmitting data through one channel. As a result, while receiving uncompressed data,
By receiving compressed data at the same time, it is possible to perform moving image display and moving image storage using compressed data while performing display and image processing using quasi-moving images using uncompressed data.

[0005]

FIG. 1 shows the configuration of an embodiment of the present invention, which will be described in detail below. The video signal output from the CCD 1 is subjected to noise removal and signal amplification in the processing unit 2. These signals are digitized by the A / D converter 3 and processed by the DSP 4. DSP unit 4
The data output from is a compression ENC that performs video compression.
(Encoder) unit 5 and tri-state buffer 9. The compression ENC unit 5 temporarily stores the input data in the frame buffer 7 and performs image compression. The data of the compression ENC unit 5 is accumulated in the buffer 6 and waits for reading from the transmission / reception LSI 20. On the other hand, the data input to the tri-state buffer 9 operates differently depending on the enable signal from the enable signal generator 17. If the enable signal is valid, the video data is output to the data format converter 10.
When the enable signal is invalid, the tri-state buffer 14 is activated by the inverter 18, so that the dummy data generation unit 13 transmits the dummy data to the data format conversion unit 10 and stores the dummy data in the buffer 11.

As described above, when the enable signal is invalid, the band is occupied by the dummy data, and the band is always secured. The enable signal is controlled by the external trigger and the video control command decoder 15. In the control by the video control command decoder 15, in order to transmit the uncompressed data, the enable signal is periodically enabled at intervals of several frames and for one frame period to transmit the uncompressed data. , DSP unit 4 to data format conversion unit 10. Here, when the input setting of the external trigger is set, the enable signal is valid for the next frame from the time when the pulse is input from the trigger input terminal. In this case, as described above, since the band is always secured, dummy data is constantly transmitted while no external trigger is input. The data format converter 10 converts the data into the data format set by the video control command decoder 15 controlled by the CPU 16 and stores the data in the frame buffer 8. The data stored in the frame buffer 8 is output to the buffer 11. The data stored in the buffer 6 and the buffer 11 are transmitted to the S.P. While switching W19, the uncompressed data and compressed data are stored in the transmission buffer of each channel inside the transmission / reception LSI 20, divided into several packets, and each data is transmitted while time-division multiplexing to two channels. .

Next, the timing until transmission of uncompressed data will be described with reference to FIGS. 4 and 5. FIG. 4 shows the timing of uncompressed data using no external trigger, and FIG. 5 shows the timing of uncompressed data using an external trigger. Both FIGS. 4 and 5 show time in the horizontal axis direction. Is shown. In FIG. 4, the uncompressed video data transmission band is reserved so that one frame of uncompressed data can be transmitted in two frame periods. The uppermost timing in FIG. 4 shows an analog video signal from the process processing unit 2, and a frame sync is set for each frame. The enable signal 1 indicates the timing of the enable signal input to the tri-state buffer 9 in FIG. In FIG. 4, the enable signal is generated once every four frames. As shown in the timing of the third video data from the top in FIG.
This video data is input to the data format converter 10 of FIG. 1 and stored in the frame buffer 11.
While the enable signal 1 is not valid, the enable signal 2 is valid. The enable signal 2 is an enable signal input to the tri-state buffer 14 of FIG. While this enable signal 2 is valid,
Dummy data must be generated. However, as shown at the timing of the fifth dummy data from the top in FIG. 4, the dummy data indicated by a broken line is determined by the relationship between the video data transmission timing and the reserved transmission band. The dummy data is discarded and the solid-line dummy data is accumulated in the frame buffer 11 of FIG. In the frame buffer 11 of FIG. 1, video data and dummy data are alternately format-converted and stored every two frame periods. The data in the frame buffer 11 corresponds to the S.B. At W19, the data is read to the transmission buffer of each channel in the transmission / reception LSI 20, similarly to the compressed data. As shown at the bottom timing of FIG. 4, these data are divided and packetized over two frame periods. Since the compressed data is packetized in the same manner, the packet of the uncompressed data and the packet of the compressed data are time-division multiplexed and transmitted.

In FIG. 5, as in FIG. 4, the transmission band of the uncompressed video data is reserved such that one frame of uncompressed data can be transmitted in two frame periods, but the external trigger is enabled. different. As shown in the second external trigger timing from the top in FIG. 5, an external trigger is input irregularly. In this figure, the external trigger is recognized at the rise of the external trigger. The next video data is transmitted to the data format conversion unit 10 from the time when the trigger is input so that there is the third enable signal 1 from the top and the fourth video data from the top, and the frame buffer 11
It is taken in. While no external trigger is being input,
Like the timing of the fifth enable signal 2 from the top in FIG. 5 and the timing of the sixth dummy data from the top, the dummy data indicated by a broken line is discarded due to the relationship between the transmission timing of video data and the reserved transmission band. , The dummy data indicated by the solid line is transmitted to the data format conversion unit 10 of FIG. The data stored in the frame buffer 11 is transmitted by the transmission / reception LSI 20 after time-division multiplexing of uncompressed data packets and compressed data packets by the transmission / reception LSI 20.

[0009]

As described above, according to the present invention, uncompressed data and compressed data are transmitted from the same video transmission device on different channels, so that moving images can be displayed and stored using the same imaged compressed data. Quasi-moving image display of an uncompressed image or image processing of a quasi-moving image can be performed. A network can be constructed by using a high-speed digital interface such as USB or IEEE1394. Therefore, a network is constructed by two video receiving devices and one video output device of the present invention, and the video receiving device 1 is used to receive each channel. By using each of them, the load on one video receiving device can be distributed. Therefore, as shown in FIG. 3, using the video receiving devices 41 and 42, the video recording devices 51 and 52, and the video transmitting device 21 of the present invention,
When a network is constructed, it is possible to display and store uncompressed data of a quasi-moving image, which was impossible in the past, while displaying and storing a moving image of an imaging target using compressed data.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an example of a conventional technique.

FIG. 3 is a schematic diagram for explaining the effect of the present invention.

FIG. 4 is a diagram for explaining timing until transmission of uncompressed data according to the present invention;

FIG. 5 is a diagram for explaining timing until transmission of uncompressed data according to the present invention;

[Explanation of symbols]

1: CCD, 2: process unit, 3: A / D converter,
4: DSP unit, 5: compression ENC unit, 6, 11: buffer, 7, 8: frame buffer, 9, 14: tri-state buffer, 10: data format conversion unit, 1
2: CCD timing generator, 13: dummy data generator, 15: video control command decoder, 16: CPU,
17: enable signal generator, 18: inverter, 2
0: LSI for transmission / reception, 21: Video transmission device.

Claims (4)

[Claims] 1. A system for outputting uncompressed data and a system for outputting data after performing data compression. The compressed data and the uncompressed data are transmitted through two channels while appropriately switching these two outputs. A video transmission device characterized by the above-mentioned. 2. The video transmission apparatus according to claim 1, further comprising a high-speed digital interface having a bandwidth guarantee mode, wherein video data of two or more channels can be transmitted simultaneously. 3. The video transmission device according to claim 1, wherein when an external trigger is input, data of a next frame can be transmitted in synchronization with a video frame synchronization signal. 4. The video transmission apparatus according to claim 1, wherein when an external trigger is not input, data of a next frame can be transmitted in synchronization with a video frame synchronization signal.